Method of using a sterilization wrap system

ABSTRACT

A method of using a sterilization wrap system including a permeable material having barrier properties and having a first surface and a second opposing surface, the exterior panel being substantially opaque or having a first level of translucence, and an interior panel including a permeable material having barrier properties and having a first surface and a second opposing surface, the interior panel having a level of translucence that is higher than the translucence of the exterior panel, the panels being joined together over at least a portion of their surfaces. Also disclosed is inspection of the sterilization wrap system for exterior panel breaches by looking for light passing through a panel facing the viewer.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/667,526, filed on Nov. 2, 2012, which claims thebenefit of priority from U.S. Provisional Application No. 61/557,215entitled “Method of Using a Sterilization Wrap System,” filed on Nov. 8,2011, and from U.S. Provisional Application No. 61/592,233 entitled“Method of Using a Sterilization Wrap System,” filed on Jan. 30, 2012,the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates in general to disposable wraps used tocontain content to be sterilized and store that content asepticallyuntil use.

BACKGROUND OF THE INVENTION

A variety of products such as gowns, sheets, drapes, instruments, etc.which are required during surgery or other aseptic procedures, are usedon a daily basis in the normal operation of hospitals, clinics and thelike. Where such products are not pre-packaged in a sterile state, it isnecessary for the hospital or clinic to sterilize them before use.Furthermore, where these products are not disposable, and are employedmore than once, it is necessary that they be cleaned and otherwiseprepared for subsequent use. Prior to such use, however, it is essentialthat such products be sterilized.

Due to the volume of materials involved, it is often necessary tosterilize and store these products for later use. Accordingly, there hasbeen developed a procedure where such products, after cleaning,laundering and the like, are wrapped in sterilization fabric and thensterilized and stored for subsequent use. Disposable sterilizationfabric is typically cut into predetermined rectangular shapes and soldas sterilization wraps.

Conventional disposable sterilization wrap is a flat, featureless sheetof material that may occasionally contain one or more additional layersof material for strength or absorbency. Such sterilization wrap isfrequently made of inexpensive, relatively impermeable material such as,for example, paper and the like. The properties of these materials havegenerally influenced folding techniques and wrapping configurations toensure the sterility of the wrapped tray or article.

For example, U.S. Pat. No. 5,635,134 to Bourne, et al. discloses amulti-ply sterilization wrap which is formed by joining one or moresheets of sterilization wrap (e.g., two separate sheets or one sheetfolded over) together to form two similarly sized, superposed panelsthat allow convenient dual wrapping of an article. As another example,U.S. Patent Application Publication No. 2001/0036519 by Robert T. Bayerdiscloses a two ply sterilization wrap that is formed of a single sheetof sterilization wrap material which is folded to form two similarlysized, superposed panels that are bonded to each other. As yet anotherexample, U.S. Patent Application Publication No. 2005/0163654 byStecklein, et al. discloses a sterilization wrap material that has afirst main panel and a second panel that is smaller than the main panel.The second panel is superposed and bonded to the central portion of themain panel such that it is contained entirely within the main panel toreinforce the main panel and/or provide additional absorbency.

There are many ways items conventionally wrapped or packaged insterilization wraps can be contaminated. For example, certain modes ofwrap failure such as knife cuts, abrasion and punctures arewell-recognized. There are other modes of failure that are as common ifnot more common. These include pressure cuts, snag cuts and pressureholes.

A pressure cut can appear as a knife cut, but upon closer examination,the fibers around the very edge of the cut have been “welded” or stucktogether. The edge of the cut may feel hard to the touch. This type ofcut usually follows the perimeter or outline of the bottom of theinstrument tray. It may also occur on the top of the instrument tray, ifa number of trays have been stacked upon one another. An example of atypical event that may generate a pressure cut would be lifting thefront end of a 20 pound tray so that all the weight of the tray isresting on a back edge, and pulling it across the storage shelf beforelifting. This is similar to cutting the wrap with scissors; the materialis caught between two layers of hard solid interfaces with a shearingaction applied to the material.

In a snag cut, the edges of the cut show loose fibers hanging and/orthere are individual fibers spanning across the width of the cut. Theedges of the cut are not rough or hard, as with the pressure cut. Inlarger snag cuts, the shape of the cut area resembles a triangle, withthe point of the triangle being where the snag began. The snag cut willoccur along the edges of the wrapped instrument tray if the tray is veryloosely wrapped. Otherwise, this type of cut will occur on the otherareas of the tray where the wrap is too loose and can be caught by roughsurfaces or corners. This type of cut is generally due to the tray beingpulled or dragged across a roughened surface, often an older, well-usedsterilizer cart. This cut can also occur when a loosely wrapped area ofa tray gets caught on the corners or edges of objects.

A pressure hole may appear to be a tiny opening where the fibers aroundthe very edge of the hole have been “welded” or stuck together. Thistype of hole is usually found along the perimeter of the bottom of aninstrument tray. It may also occur on the top of the instrument tray ifa number of trays have been stacked upon it. An example of a typicalevent that may generate a pressure hole would be a tray being dropped(even a small distance) onto an edge of a cart or storage shelf whilebeing transported to different areas of the hospital.

During typical practice, the sterilization wrap is inspected for holes,tears or other breaches after it is removed from the sterilized article.It has been proposed in International Publication No. WO 2008/083426 A1“Sterilization Wrapping System” by Spierenburg, that having colordifferences between superposed layers of a sterilization wrap systemcould make detection of breaches easier because a viewer lookingdirectly at a breach will notice the contrast between the color of thematerial around the breach and the material exposed by the breach.However, such a system fails to address the problem of detectingbreaches in the sheet of a multi-layer sterilization wrap on theopposite side of the viewer such that the viewer cannot look directly atthe breach to see the difference in color.

Accordingly, there is an unmet need for an easy method to inspect asterilization assembly, package or system that simplifies the task ofidentifying a breach—particular a breach in a multi-layer sterilizationwrap system that is on the opposite side of a viewer.

BRIEF SUMMARY OF THE INVENTION

The problems described above are addressed by the present inventionwhich encompasses a method of using a sterilization wrap system. Themethod includes the steps of providing an article and then wrapping thearticle with a sterilization wrap system having an exterior panelincluding a permeable material having barrier properties and having afirst surface and a second opposing surface, the exterior panel beingsubstantially opaque or having a first level of translucence; and aninterior panel including a gas permeable material having barrierproperties and having a first surface and a second opposing surface, theinterior panel having a level of translucence that is higher than thetranslucence of the exterior panel, the panels being joined togetherover at least a portion of their surfaces. The method further includesthe steps of exposing the wrapped article to sterilizing conditions fora sufficient time such that the article is sterilized; unwrapping thearticle and removing the sterilization wrap system; positioning thesterilization wrap system so at least a portion of the exterior panel ofthe sterilization wrap system is opposite a viewer and a correspondingportion of the interior panel is facing a viewer; and inspecting thesterilization wrap system for exterior panel breaches by looking forlight passing through the interior panel facing the viewer.

The sterilization wrap system is desirably positioned so that thesterilization wrap system is located between a light source and aviewer. In an aspect of the invention, the sterilization wrap system maybe positioned so that the first panel and the second panel are separatedby a space in a portion of the sterilization wrap system beinginspected.

According to the invention, the second panel includes a plurality ofbond points and the bond points define discrete locations having highertranslucence than locations on the permeable material of the secondpanel that are not bond points such that inspecting the sterilizationwrap system for exterior panel breaches is carried out by looking forlight passing through a panel facing the viewer by way of one or morebond points.

The present invention also encompasses a method of inspecting asterilization wrap system after it is removed from an article. Themethod includes the steps of: positioning a sterilization wrap systemwith respect to a viewer (that is, a sterilization wrap system includinga first panel composed of a gas permeable material having barrierproperties and having a first surface and a second opposing surface, thefirst panel being substantially opaque or having a first level oftranslucence; and a second panel composed of a permeable material havingbarrier properties and having a first surface and a second opposingsurface, the second panel having a level of translucence that is higherthan the translucence of the first panel, wherein the panels are joinedtogether over at least a portion of their surfaces and wherein at leasta portion of one panel of the sterilization wrap system is opposite aviewer and a corresponding portion of the other panel is facing aviewer); and inspecting the sterilization wrap system for breaches inthe panel opposite the viewer by looking for light passing through thepanel facing the viewer.

The sterilization wrap system is desirably positioned so that thesterilization wrap system is located between a light source and aviewer. In an aspect of the invention, the sterilization wrap system maybe positioned so that the first panel and the second panel are separatedby a space in a portion of the sterilization wrap system beinginspected.

According to another aspect of the invention, the first panel, thesecond panel or both panels may include a plurality of bond points andthe bond points define discrete locations having higher translucencethan locations on the permeable material of the respective first orsecond panel that are not bond points such that inspecting thesterilization wrap system for breaches in the panel opposite the vieweris carried out by looking for light passing through the panel facing theviewer by way of one or more bond points. According to the invention,the first panel may be opposite the viewer and the second panel may befacing the viewer. Alternatively, the first panel may be facing theviewer and the second panel may be opposite the viewer.

The present invention also encompasses a sterilization wrap system thatincludes: a first panel having a permeable material having barrierproperties and having a first surface and a second opposing surface, thefirst panel being substantially opaque or having a first level oftranslucence; and a second panel including a permeable material havingbarrier properties and having a first surface and a second opposingsurface, the second panel having a level of translucence that is higherthan the translucence of the first panel, the panels being joinedtogether over at least a portion of their surfaces.

The second panel may include a plurality of bond points. These bondpoints define discrete locations having higher translucence thanlocations on the permeable material of the second panel that are notbond points. For example, the plurality of bond points on the secondpanel may provide the second panel with at least 15 percent highertranslucence than locations on the permeable material of the secondpanel that are not bond points. As another example, the plurality ofbond points on the second panel may provide the second panel with atleast 30 percent higher translucence. As yet another example, pluralityof bond points on the second panel may provide the second panel with atleast 45 percent higher translucence.

In an aspect of the invention, the permeable material of the secondpanel may be a permeable material that has a higher level oftranslucence than the permeable material of the first panel. Forexample, the difference in translucence between first panel and thesecond panel may be at least 15 percent. As another example, thedifference in translucence between first panel and the second panel maybe at least 30 percent. As yet another example, the difference intranslucence between first panel and the second panel may be at least 45percent.

Desirably, the sterilization system is adapted for use in steamsterilizing conditions, ethylene oxide sterilizing conditions, as wellas other conventional sterilizing systems.

According to an aspect of the invention, the first panel and the secondpanel may be a single sheet of permeable material having barrierproperties, the single sheet being folded to form a first panel andsecond panel and at least the edges opposite the fold being joinedtogether. In another aspect of the invention, the first panel and thesecond panel may be independent sheets of material that are joinedtogether. For example, the first panel and second panel may each have aperiphery and the first panel and second panel may be overlaid andjoined at the periphery. Desirably, at least one of the permeablematerials having barrier properties is a spunbond/meltblown/spunbond(SMS) material.

The present invention also encompasses a sterilization wrap systemcomposed of a permeable material having barrier properties and thepermeable material includes: a first sheet having a first surface and asecond opposing surface, the first material being substantially opaqueor having a first level of translucence; and a second sheet having afirst surface and a second opposing surface, the second sheet having alevel of translucence that is higher than the translucence of the firstsheet, the sheets being joined together over at least a portion of theirsurfaces.

The second sheet may include a plurality of bond points such that thebond points define discrete locations having higher translucence thanlocations on the second sheet that are not bond points. For example, theplurality of bond points on the second sheet may provide the secondsheet with at least 15 percent higher translucence than locations on thesecond sheet that are not bond points. As another example, the pluralityof bond points on the second sheet may provide the second sheet with atleast 30 percent higher translucence. As yet another example, theplurality of bond points on the second sheet may provide the secondsheet with at least 45 percent higher translucence.

In an aspect of the invention, the first sheet may be made of a firstpermeable material and the second sheet may be made of a secondpermeable material that has a higher level of translucence than thefirst material. For example, the difference in translucence betweenfirst sheet and the second sheet may be at least 15 percent. As anotherexample, the difference in translucence between first sheet and thesecond sheet may be at least 30 percent. As yet another example, thedifference in translucence between first sheet and the second sheet maybe at least 45 percent.

In an aspect of the invention, the first sheet and the second sheet maybe a single sheet of permeable material having barrier properties, thesingle sheet being folded over to form a first sheet and second sheetand at least the edges opposite the fold being joined together. Inanother aspect of the invention, the first sheet and the second sheetmay be independent sheets of material that are joined together. Forexample, the first sheet and second sheet may each have a periphery andthe first sheet and second sheet may be overlaid and joined at theperiphery. Desirably, at least one of the permeable materials havingbarrier properties is a spunbond/meltblown/spunbond material.

The present invention also encompasses a method of making asterilization wrap system. The method includes the steps of: providing afirst panel including a permeable material having barrier properties andhaving a first surface and a second opposing surface, the first panelbeing substantially opaque or having a first level of translucence;providing a second panel including a permeable material having barrierproperties and having a first surface and a second opposing surface, thesecond panel having a level of translucence that is higher than thetranslucence of the first panel; and joining the panels together over atleast a portion of the their surfaces.

The second panel may be bonded or provided with a plurality of bondpoints and the bond points define discrete locations having highertranslucence than locations on the permeable material of the secondpanel that are not bond points. The first panel and the second panel maybe provided as a single sheet of permeable material having barrierproperties, the single sheet may then be folded over to form a firstpanel and second panel and at least the edges opposite the fold joinedtogether. Alternatively, the first panel and the second panel may beprovided as independent sheets of material which may be joined together.For example, the first panel and second panel may each have a peripheryand the first panel and second panel may be overlaid and joined at theperiphery.

These and other features and advantages of the invention will becomemore apparent to one skilled in the art from the following descriptionand claims when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood by reading the DetailedDescription of the Invention with reference to the accompanying drawingfigures, in which like reference numerals denote similar structure andrefer to like elements throughout, and in which:

FIG. 1 is a perspective view illustration of an exemplary sterilizationwrap system.

FIG. 2 is a perspective view illustration of another exemplarysterilization wrap system.

FIG. 3 is top view illustration of an exemplary bond pattern.

FIG. 4 is top view illustration of another exemplary bond pattern.

FIG. 5 is top view illustration of another exemplary bond pattern.

FIG. 6 is top view illustration of another exemplary bond pattern.

FIG. 7 is a side view illustration of an exemplary method of using orinspecting a sterilization wrap system.

FIG. 8 is a side view illustration of another exemplary method of usingor inspecting a sterilization wrap system.

FIG. 9 is an illustration of a graph of data and information from Table2.

FIG. 10 is an illustration of a graph of data and information from Table3.

FIG. 11 is an illustration of a graph of data and information from Table2 and Table 4.

FIG. 12 is an illustration of a graph of data and information from Table2, Table 4 and Table 5.

FIG. 13 is an illustration of a graph of data and information from Table6.

FIG. 14 is an illustration of a graph of data and information from Table7.

FIG. 15 is an illustration of a graph of data and information fromTables 7 and 8.

FIG. 16 is an illustration of a graph of data and information from Table9.

FIG. 17 is an illustration of a graph of data and information from Table10.

DEFINITIONS

As used herein, the term “disposable” refers to a product that is soinexpensive that it may economically be discarded after only a singleuse. Products that are “disposable” are typically intended for singleuse. The term “single-use” refers to a product that is intended to beused for only once and is not intended to be re-used, re-conditioned,restored or repaired after that use. These products offer advantages inclinical settings by reducing the potential for contamination orinfection. In addition, these products can enhance work flow since theyare not collected and assembled for reprocessing and reuse.

As used herein, the term “sterilization wrap” refers to a flexiblearticle composed of fabric(s) and/or flexible material(s) that iswrapped around, folded around or otherwise encloses a non-sterilearticle or non-sterile content prior to sterilization. A sterilizationwrap may have multiple panels and/or sections providing specificphysical properties, functional characteristics and/or structure thatprovide advantages for wrapping or folding, handling, strength,sterilization, storage after sterilization, and/or unwrapping orunfolding.

As used herein, the term “nonwoven web” refers to a web that has astructure of individual fibers or filaments which are interlaid, but notin an identifiable repeating manner. Nonwoven webs have been, in thepast, formed by a variety of processes known to those skilled in the artsuch as, for example, meltblowing, spunbonding and bonded carded webprocesses.

As used herein, the term “spunbonded web” refers to a web of smalldiameter fibers and/or filaments which are formed by extruding a moltenthermoplastic material as filaments from a plurality of fine, usuallycircular, capillaries in a spinnerette with the diameter of the extrudedfilaments then being rapidly reduced, for example, by non-eductive oreductive fluid-drawing or other well-known spunbonding mechanisms. Theproduction of spunbonded nonwoven webs is illustrated in patents such asAppel, et al., U.S. Pat. No. 4,340,563; Dorschner et al., U.S. Pat. No.3,692,618; Kinney, U.S. Pat. Nos. 3,338,992 and 3,341,394; Levy, U.S.Pat. No. 3,276,944; Peterson, U.S. Pat. No. 3,502,538; Hartman, U.S.Pat. No. 3,502,763; Dobo et al., U.S. Pat. No. 3,542,615; and Harmon,Canadian Patent No. 803,714.

As used herein, the term “meltblown fibers” means fibers formed byextruding a molten thermoplastic material through a plurality of fine,usually circular, die capillaries as molten threads or filaments into ahigh-velocity gas (e.g. air) stream which attenuates the filaments ofmolten thermoplastic material to reduce their diameters, which may be tomicrofiber diameter. Thereafter, the meltblown fibers are carried by thehigh-velocity gas stream and are deposited on a collecting surface toform a web of randomly disbursed meltblown fibers. The meltblown processis well-known and is described in various patents and publications,including NRL Report 4364, “Manufacture of Super-Fine Organic Fibers” byV. A. Wendt, E. L. Boone, and C. D. Fluharty; NRL Report 5265, “AnImproved device for the Formation of Super-Fine Thermoplastic Fibers” byK. D. Lawrence, R. T. Lukas, and J. A. Young; and U.S. Pat. No.3,849,241, issued Nov. 19, 1974, to Buntin, et al.

As used herein, “ultrasonic bonding” means a process performed, forexample, by passing the fabric between a sonic horn and anvil roll asillustrated in U.S. Pat. No. 4,374,888 to Bornslaeger, the entirecontents of which is incorporated herein by reference.

As used herein “point bonding” means bonding one or more layers offabric at a plurality of discrete bond points. For example, thermalpoint bonding generally involves passing a fabric or web of fibers to bebonded between a heated roll assembly such as, for example, a heatedcalender roll and an anvil roll. The calender roll is usually patternedin some way so that the entire fabric is not bonded across its entiresurface, and the anvil roll is usually smooth. As a result, variouspatterns for calender rolls have been developed for functional and/oraesthetic reasons. One example of a pattern has points and is the HansenPennings or “H&P” pattern with about a 30% bond area with about 200bonds/square inch (31 bonds/square cm) as taught in U.S. Pat. No.3,855,046 to Hansen and Pennings. Another example is shown in U.S.Design Pat. No. 239,566 to Vogt. Typically, the percent bonding areavaries from around 5% to around 30% of the area of the fabric laminateweb. Spot bonding holds the laminate layers together as well as impartsintegrity to each individual layer by bonding filaments and/or fiberswithin each layer without destroying the breathability or hand of thefabric.

As used herein “opacity” means the optical density of a material and isthe opposite of transparency. A material having high opacity or which isopaque has good hiding or covering power in that it can conceal anotherarticle, tint or shade over which it is applied. A material havinggreater opacity will have greater impenetrability to electromagneticradiation in the visible spectrum. A substantially opaque material willallow very little light to pass through. For example, the lighttransmittance (visible spectrum) of a substantially opaque material suchas a substantially opaque nonwoven fabric will generally be less thanabout 25% as measured using a conventional color meter spectrophotometersuch as, for example, a HunterLab D25 optical sensor and a HunterLabDP-9000 processor available from HunterLab Associates, Inc., Reston, Va.As another example, the light transmittance of a substantially opaquenonwoven fabric will generally be less than about 20%. As yet anotherexample, the light transmittance of a substantially opaque nonwovenfabric will generally be less than about 15%. Desirably, the lighttransmittance of a substantially opaque nonwoven fabric will generallybe less than about 10% and may be between 10% and 5%.

As used herein, “translucence” or “translucent” means the lighttransmittance or optical density of a material which is in a rangebetween substantially transparent and substantially opaque. Generallyspeaking, translucent materials allow light to pass through diffuselywhereas substantially transparent materials appear clear. A materialthat is translucent will allow a greater level of electromagneticradiation in the visible spectrum to pass through it than an opaque orsubstantially opaque material but will allow a lower level ofelectromagnetic radiation in the visible spectrum to pass through itthan a transparent or substantially transparent material. For example,the light transmittance (visible spectrum) of a translucent materialsuch as a nonwoven fabric having translucence and a satisfactory levelof barrier properties will generally be greater than about 30% asmeasured using a conventional color meter spectrophotometer such as, forexample, a HunterLab D25 optical sensor and a HunterLab DP-9000processor available from HunterLab Associates, Inc., Reston, Va. Thelight transmittance is expressed as a percentage and determined usingthe following formula: Light Transmittance=(100−Percent Opacity). Thus,a material having a percent opacity of 70% has a light transmittance of30%. As another example, the light transmittance of a nonwoven fabrichaving translucence and a satisfactory level of barrier properties willgenerally be greater than about 35%. As yet another example, the lighttransmittance of a nonwoven fabric having translucence and asatisfactory level of barrier properties will generally be greater thanabout 40% (e.g., 50%, 60% or even 70%). Desirably, the lighttransmittance of a nonwoven fabric having translucence and asatisfactory level of barrier properties will generally be from about30% to about 60%.

DETAILED DESCRIPTION OF INVENTION

In describing the various embodiments of the present invention, asillustrated in the figures and/or described herein, specific terminologyis employed for the sake of clarity. The invention, however, is notintended to be limited to the specific terminology so selected, and itis to be understood that each specific element includes all technicalequivalents that operate in a similar manner to accomplish similarfunctions.

Referring now to FIG. 1, there is shown an exemplary sterilization wrapsystem 10 which includes an exterior panel 12 and an interior panel 14.FIG. 2 is an illustration of another exemplary sterilization wrap systemwhich may be in the form of a multi-panel sterilization assembly such asdescribed in U.S. Patent Application Publication No. US2011/0033137A1for a “Flexible Multi-Panel Sterilization Assembly” published on Feb.10, 2011, the entire contents of which are incorporated herein byreference. Referring to FIG. 2, the sterilization wrap system 10 mayhave an exterior panel 12 and a second panel 12. Other details of theassembly are not shown to simplify the description.

The exterior panel 12 is made of or includes a permeable material havingbarrier properties and has a first surface 16 and a second opposingsurface 18. The exterior panel 12 may be substantially opaque or willhave a first level of translucence. The interior panel 14 is made of orincludes a permeable material having barrier properties and has a firstsurface 20 and a second opposing surface 22. The interior panel 14 has alevel of translucence that is higher than the translucence of the firstpanel. The panels may be joined together over at least a portion oftheir surfaces.

In an aspect of the invention, the permeable material of the interiorpanel 14 may be a permeable material that has a higher level oftranslucence than the permeable material of the exterior panel 12. Forexample, the difference in translucence as expressed in terms of lighttransmittance between first panel and the second panel may be at least15 percent. As another example, the difference in translucence betweenfirst panel and the second panel may be at least 30 percent. As yetanother example, the difference in translucence between first panel andthe second panel may be at least 45 percent. The difference intranslucence between first panel and the second panel may be 75 percentor more. For example, the difference in translucence between first paneland the second panel may be 250 percent or more. As another example, thedifference in translucence between first panel and the second panel maybe 500 percent or more.

Referring now to FIGS. 3-6, there is illustrated (not to scale) theinterior panel 14 and a plurality of bond points 100 that may be locatedon the second panel. These bond points 100 define discrete locationshaving higher translucence than locations 102 on the permeable materialof the second panel that are not bond points. This may be bestillustrated in FIGS. 3 and 6. The exterior panel 12 may be similarlybonded.

One characteristic of the second panel is that it has a total bond areaof about 30 percent and a relatively uniform bond density of greaterthan about 100 bonds per square inch. For example, the second panel mayhave a total bond area from about 10 to about 40 percent (as determinedby conventional optical microscopic methods) and a bond density fromabout 100 bonds to about 500 pin bonds per square inch.

Such a combination total bond area and bond density may be achieved bybonding the continuous filament substrate with a pin bond pattern havingmore than about 100 pin bonds per square inch which provides a totalbond surface area less than about 30 percent when fully contacting asmooth anvil roll. Desirably, the bond pattern may have a pin bonddensity from about 150 to about 250 pin bonds per square inch and atotal bond surface area from about 10 percent to about 25 percent whencontacting a smooth anvil roll.

One example of a pattern is the Hansen Pennings or “H&P” pattern withabout a 30% bond area with about 200 bonds/square inch (31 bonds/squarecm) as taught in U.S. Pat. No. 3,855,046 to Hansen and Pennings, thecontents of which are incorporated by reference. Another example isshown in U.S. Design Pat. No. 239,566 to Vogt and illustrated in FIG. 3above which is identified as the “RHT” pattern. The bond area for theRHT pattern is about 20%±10%. Typically, the percent bonding area variesfrom around 5% to around 30% of the area of the fabric laminate web.

An exemplary bond pattern is shown in FIG. 4 (714 pattern). That bondpattern has a pin density of about 306 pins per square inch. Each pindefines square bond surface having sides which are about 0.025 inch inlength. When the pins contact a smooth anvil roller they create a totalbond surface area of about 15.7 percent. High basis weight substratesgenerally have a bond area which approaches that value. Lower basisweight substrates generally have a lower bond area. FIG. 5 is anotherexemplary bond pattern (WW13 pattern). The pattern of FIG. 5 has a pindensity of about 278 pins per square inch. Each pin defines a bondsurface having 2 parallel sides about 0.035 inch long (and about 0.02inch apart) and two opposed convex sides—each having a radius of about0.0075 inch. When the pins contact a smooth anvil roller they create atotal bond surface area of about 17.2 percent. FIG. 6 is another bondpattern which may be used. The patter of FIG. 6 has a pin density ofabout 103 pins per square inch. Each pin defines a square bond surfacehaving sides which are about 0.043 inch in length. When the pins contacta smooth anvil roller they create a total bond surface area of about16.5 percent.

According to the invention, the plurality of bond points 100 on theinterior panel 14 may provide the second panel with at least 15 percenthigher translucence than locations 102 on the permeable material of thesecond panel that are not bond points. As another example, the pluralityof bond points on the second panel may provide the second panel with atleast 30 percent higher translucence. As yet another example, pluralityof bond points on the second panel may provide the second panel with atleast 45 percent higher translucence. As yet another example, thedifference in translucence may be 75 percent or more. For example, thedifference in translucence may be 250 percent or more. As anotherexample, the difference in translucence may be 500 percent or more.

Desirably, the sterilization system is adapted for use in steamsterilizing conditions, ethylene oxide sterilizing conditions, as wellas other conventional sterilizing systems.

According to an aspect of the invention, the exterior panel 12 and theinterior panel 14 may be a single sheet of permeable material havingbarrier properties and the single sheet being folded to form an exteriorpanel 12 and interior panel 14 and at least the edges opposite the foldbeing joined together. In another aspect of the invention, the exteriorpanel 12 and the interior panel 14 may be independent sheets of materialthat are joined together. For example, the exterior panel 12 andinterior panel 14 may each have a periphery 24 and the exterior panel 12and interior panel 14 may be overlaid and joined at the periphery 24.Desirably, at least one of the permeable materials having barrierproperties is a spunbond/meltblown/spunbond material.

In important aspect of the present invention is the method of using asterilization wrap system. The method includes the steps of providing anarticle and then wrapping the article with a sterilization wrap system10 having an exterior (or first) panel 12 including a permeable materialhaving barrier properties and having a first surface 16 and a secondopposing surface 18, the exterior panel 12 being substantially opaque orhaving a first level of translucence; and an interior (or second) panel14 including a permeable material having barrier properties and having afirst surface 20 and a second opposing surface 22, the interior panel 14having a level of translucence that is higher than the translucence ofthe exterior panel 12, the panels being joined together over at least aportion of their surfaces.

The method further includes the steps of exposing the wrapped article tosterilizing conditions for a sufficient time such that the article issterilized. The sterilized article may be stored or it may be deliveredto an operating room or other location. The method includes the step ofunwrapping the article and removing the sterilization wrap system.

Referring now to FIG. 7, the method includes the step of positioning thesterilization wrap system 10 so at least a portion of the exterior panel12 of the sterilization wrap system 10 is opposite a viewer “V” and acorresponding portion of the interior panel 14 is facing a viewer “V”;and inspecting the sterilization wrap system 10 for breaches 30 in theexterior panel 12 by looking for light “L” passing through the interiorpanel 14 facing the viewer.

The sterilization wrap system is desirably positioned so that thesterilization wrap system is located between a light source “LS” and aviewer “V”. In an aspect of the invention illustrated in FIG. 8, thesterilization wrap system 10 may be positioned or held or manipulated sothat the first panel and the second panel are separated by a space 32 ina portion of the sterilization wrap system being inspected.

According to the invention, the second panel may include a plurality ofbond points 100 and the bond points define discrete locations havinghigher translucence than locations 102 on the permeable material of theinterior panel 14 (or second panel) that are not bond points such thatinspecting the sterilization wrap system for exterior panel breaches iscarried out by looking for light passing through the interior panel 14facing the viewer by way of one or more bond points.

The present invention also encompasses a method of inspecting asterilization wrap system 10 for breaches after it is removed from anarticle. The method includes the steps of: positioning a sterilizationwrap system 10 with respect to a viewer (that is, a sterilization wrapsystem including an exterior panel 12 composed of a permeable materialhaving barrier properties and having a first surface 16 and a secondopposing surface 18, the exterior panel 12 being substantially opaque orhaving a first level of translucence; and a interior panel 14 composedof a permeable material having barrier properties and having a firstsurface 20 and a second opposing surface 24, the interior panel 14having a level of translucence that is higher than the translucence ofthe exterior panel 12, wherein the panels are joined together over atleast a portion of their surfaces and wherein at least a portion of onepanel of the sterilization wrap system 10 is opposite a viewer “V” and acorresponding portion of the other panel is facing a viewer “V”); andinspecting the sterilization wrap system 10 for breaches 30 in a panelby looking for light “L” passing through the panel facing the viewer“V”.

The sterilization wrap system is desirably positioned so that thesterilization wrap system 10 is located between a light source “LS” anda viewer “V”. In an aspect of the invention, the sterilization wrapsystem 10 may be positioned so that the exterior panel 12 and theinterior panel 14 are separated by a space 32 in a portion of thesterilization wrap system being inspected.

According to another aspect of the invention, the exterior panel 12, theinterior panel 14 or both panels (12 and 14) may include a plurality ofbond points 100 and the bond points define discrete locations havinghigher translucence than locations 102 on the permeable material of therespective first or second panel that are not bond points such thatinspecting the sterilization wrap system for breaches in a panel iscarried out by looking for light “L” passing through the panel facingthe viewer “V” by way of one or more bond points 100. According to theinvention, the exterior panel 12 may be opposite the viewer “V” and theinterior panel 14 may be facing the viewer “V”. Alternatively, theexterior panel 12 may be facing the viewer “V” and the interior panel 14may be opposite the viewer “V”.

The present invention also encompasses a method of making asterilization wrap system. The method includes the steps of: providingan exterior panel 12 including a permeable material having barrierproperties and having a first surface 15 and a second opposing surface18, the exterior panel 12 being substantially opaque or having a firstlevel of translucence; providing an interior panel 14 including apermeable material having barrier properties and having a first surface20 and a second opposing surface 22, the interior panel 14 having alevel of translucence that is higher than the translucence of theexterior panel 12; and joining the panels together over at least aportion of the their surfaces.

The second panel may be bonded or provided with a plurality of bondpoints 100 and the bond points define discrete locations having highertranslucence than locations 102 on the permeable material of the secondpanel that are not bond points. The exterior panel 12 and the interiorpanel 14 may be provided as a single sheet of permeable material havingbarrier properties. The single sheet may then be folded over to form anexterior panel 12 and interior panel 14 and at least the edges oppositethe fold joined together. Alternatively, the first panel and the secondpanel may be provided as independent sheets of material which may bejoined together. For example, the exterior panel 12 and interior panel14 may each have a periphery 25 and the first panel and second panel maybe overlaid and joined at the periphery 24.

EXAMPLES

Aspects of the invention were evaluated in the following examples.

An exemplary wrap was made from two stacked panels (also refers to as“plies” or individually as “ply”) of gas permeable nonwoven fabric. Eachply/panel of the fabric had barrier properties with respect to microbecontaminates. Each ply also was made from polypropylene or otherdimensionally stable thermoplastic polymers at temperature typical ofsteam sterilization (they do not shrink). In addition, each ply/panelhad relative differences in color: one lighter than the other. Theopacity of the interior ply (which was lighter colored) was less thanthe exterior ply. In this example, each play was thermally bonded sothat the bonded areas become more translucent (less opaque) than theunbonded areas.

Exemplary plies or panels are laminate material composed of thermallypoint bonded layers of spunbond material sandwiching a layer ofmeltblown material (also referred to as “SMS” material). One ply formsthe exterior side, (to be the outside of the wrap when envelopingcontents) and the other ply forms the interior side (to be the inside ofthe wrap when enveloping contents); The exterior ply is a dark color(e.g. blue) relative to the interior ply (e.g. white) so that theinterior ply always has less opacity than the exterior ply.

This stacking arrangement of a dark colored exterior ply against alighter colored interior ply makes a breach in the exterior ply, e.g.due to a tear or hole in the exterior ply, easier to detect through theinterior ply compared to two stacked plies of the same color.

The invention is illustrated via an exterior ply of SMS that is blueagainst an interior ply of similar dimensioned SMS that is white andless opaque (i.e., more translucent), and the plies are attachedtogether at least near one common edge. Examples of suitable exteriorand interior SMS plies are shown in Table 1. The basis weight isreported in ounces per square yard (osy)—which may be converted to gramsper square meter by multiplying the osy value by 33.91. The amount ofmeltblown (MB) in the SMS ranges from 14 to 35%.

TABLE 1 Ply Target Component Basis Weights Basis Weight SB layer 1 MBcenter layer SB layer 2 Example Color (osy) (osy) (osy) (osy) % MBExterior 1 Light Blue 1.05 0.378 0.294 0.378 28% Exterior 2 Light Blue1.20 0.432 0.336 0.432 28% Exterior 3 Mid-range 1.40 0.455-0.5040.392-0.490 0.455-0.504 28-35% Blue Exterior 4 Mid-range 1.850.694-0.759 0.333-0.463 0.694-0.759 18-25% Blue Exterior 5 Dark Blue2.05 0.769-0.851 0.349-0.513 0.769-0.851 17-25% Exterior 6 Dark Blue2.57 0.964-1.106 0.360-0.643 0.964-1.106 14-25% Interior 1 White 1.050.378 0.294 0.378 28% Interior 2 White 1.20 0.432 0.336 0.432 28%Interior 3 White 1.40 0.455-0.504 0.392-0.490 0.455-0.504 28% Interior 4White 1.85 0.694-0.759 0.333-0.463 0.694-0.759 18-25% Interior 5 White2.05 0.769-0.851 0.349-0.513 0.769-0.851 17-25% Interior 6 White 2.570.964-1.106 0.360-0.643 0.964-1.106 14-25%

The relative opacity (Opacity), or conversely translucence (which isexpressed as Translucence=100−percent opacity), of Exterior and InteriorExample plies from Table 1 and selected stacked combinations weremeasured via a conventional color meter spectrophotometer. One suitablespectrophotometer is a HunterLab D25 optical sensor and a HunterLabDP-9000 processor available from HunterLab Associates, Inc., Reston, Va.The D25 optical sensor detects red, green, and blue signal data and theDP-9000 processor receives the signal data and converts the data into X,Y, and Z values per the CIE Tristimulus XYZ Scale. Equipment set-upfollowed conventional practices except that the specimen port wasreduced to 0.75 inch diameter opening via an area view insert (alsoavailable from HunterLab Associates, Inc.). Appropriate black glass andwhite calibrated tiles were used for standardization procedures and fortaking measurements per the manufacturer's instructions or otheraccepted standards of practice. Measurements were taken using 2colorimeter units, 1 & 2, in different locations but otherwise of thesame make and model.

The above spectrophotometer arrangement yields a Y value for a sampleplaced over the reduced specimen port backed by the black glass andanother Y value for the same placed sample backed by the white tile;comparing these Y values according “contrast ratio method” yields“opacity” for the sample. The contrast ratio method divides the Y valuefor the sample backed by the black glass by the Y value for the samesample backed by the white tile, and this ratio is then multiplied by100.

Table 2 lists the Opacity values averaged for the samples of the Table 1Examples (each as a single ply) and FIG. 9 is a graph illustrating theirrelationship via the Avg values; at equivalent basis weights theInterior Examples (white) have less opacity than the Exterior Examples(blue). The averages for Colorimeter 1 are of two samples, those forColorimeter 2 are three samples, and the Avg values represent theaverage of all five samples.

TABLE 2 Relative Opacity Exterior Examples Interior Examples (SMS Blue)(SMS White) Colorimeter Basis Wgt, osy 1 2 Avg 1 2 Avg 1.05 56.845 —56.845 54.915 — 54.915 1.2 66.355 66.433 66.402 58.94 58.567 58.716 1.478.080 74.083 75.682 68.085 66.707 67.258 1.85 87.900 85.223 86.29469.975 67.027 68.206 2.05 94.255 93.187 93.614 67.725 67.207 67.414 2.5794.150 93.463 93.738 71.765 70.537 71.028

Samples representative of the invention were made by stacking anInterior ply (white) on top of an Exterior ply (blue). Comparativesamples were also made by stacking 2 plies on the same color one on topof the other and reversing the arrangement of the samples of theinvention (blue on top of white).

In order to demonstrate the aspect of the present invention related tofacilitating breach detection in the Exterior ply by detection of lightthrough the Interior ply, a 1.4 mm hole diameter was made (via a pointedrod) in selected Exterior plies for the samples representative of theinvention. A 1.4 mm hole diameter was made (via a pointed rod) inselected Exterior plies for the comparative examples as well.

Opacity measurements were made for the stacked 2 plies with the Exteriorply immediately placed against the specimen port of the spectrometer,the Interior ply above the Exterior ply, and the backing plate (blackglass, the white tile) on top. The samples and their Opacity values arelisted in Table 3; values for Colorimeter 1 represent individualmeasurements; values for Colorimeter 2 represent an average of at leasttwo measurements. Their relationships are shown using the averagedColorimeter 2 averages when possible in FIG. 10 of the drawings.

TABLE 3 Opacity for 2 plies, each ply at: 1.2 osy 1.85 osy 2.56 osyDescription of Colorimeter Exterior/Interior 1 2 1 1 2 Invention SetBlue/White 82.55 82.02 94.71 98.51 97.62 Comp. Set 1 White/Blue 90.3189.35 98.9 97.84 99.74 Comp. Set 2 Blue/Blue 90.68 — 98.39 99.79 — Comp.Set 3 White/White 79.04 — 83.8 87.21 — Invention Set with breach B/W w1.4 mm Hole 82.92 82.55 94.22 96.88 96.78 Comp Set 1 with breach W/B w1.4 mm Hole 90.17 89.03 97.71 99.78 99.11 Comp. Set 2 with breach B/B w1.4 mm Hole — — 97.85 99.55 —

The information in Tables 4-6 highlight the improvement in translucenceprovided by point bonding. The point bonding for all the samples usedthe same bonding pattern, the RHT pattern, which imparted ˜20% bondedarea (80% remaining unbonded).

Table 4A lists the Opacity values per: Colorimeter 1 as averages of twosamples, except as noted by an asterisk (*); Colorimeter 2 as averagesof three samples; and Avg as the average of Colorimeter 1 & 2measurements. The different types of samples tested were: 100% whitepolypropylene meltblown fabric (MB) at different basis weights that wereunbonded (i.e., no bonded regions); a 100% white polypropylene MB havinga basis weight of 1 osy that was thermally point bonded; and a sample ofthe Blue Exterior Example at 2.57 osy (a retest to determinereproducibility of Table 2 Opacity values). The asterisk (*) representsOpacity values for only one sample per Colorimeter 1.

TABLE 4A % Opacity per Sample Description Basis Colorimeter: NumberColor Bonded Fabric Wgt, osy 1 2 Avg 7 White None MB 0.29 — 50.59 50.598 White None MB 0.44 — 57.82 57.82 9 White None MB 0.59 — 68.45 68.45 10White None MB 0.74 77.96 76.47 77.07 6 White None MB 1.04 — 86.21 86.2111 White None MB 1.18 87.17 84.37 85.49 12 White None MB 1.62 90.6189.69 90.06 5 White None MB 2.56 — 95.25 95.25 13 White Point MB 1 70.5768.78 69.50 14 Blue Point SMS* 2.57 94.09 93.46 93.62

Table 4B lists Opacity averages per Colorimeter 2 of three samples forthe MB fabric of Sample Number 5-9 after each fabric was thermally pointbonded using the pattern of FIG. 3, which matched the pattern for theother Point Bonded fabrics. The Sample Numbers of Table 4B correspondrespectively to those of Table 4A (e.g. 7B samples were made from thefabric for Sample Number 7 of Table 4A).

TABLE 4B Sample Description Basis Wgt, % Opacity per Number Color BondedFabric osy Colorimeter 2 7B White Point MB 0.29 45.07 8B White Point MB0.44 56.58 9B White Point MB 0.59 63.10 6B White Point MB 1.04 73.70 5BWhite Point MB 2.56 80.72

Table 5 lists Opacity values per Colorimeter 1 for samples listed inTable 2 and Table 5 that were subsequently “filmed” so that each samplewas 100% bonded. The term “filmed” means that the samples weresandwiched between thin metal foil strips (one rigid for support, theother aluminum foil) and passed through commercially available desktoplaminator that heated and pressed the sandwiched sample. The combinationof heat and pressure resulted in a fusing of individual fibers andfilaments into a sheet that has the appearance of a film. The purpose ofthis procedure is to determine a level of opacity of the polymericmaterial that forms the nonwoven fabric (e.g., MB or SMS) by eliminatingthe fibrous structure formed of individual fibers or filaments in thenonwoven fabric. The asterisk (*) represents Opacity values for only onesample. Samples that are described as “Point and Filmed”, the sampleinitially had Point Bonds present in the material prior to being“filmed”. Samples that that are described only as “Filmed” were unbondedmaterials (i.e., contained no point bonds) prior to being “filmed.”

TABLE 5 Sample Description Number Source Color Bonded Fabric Basis Wgt,osy % Opacity 15 Sample 13 White Point & Filmed MB 1 3.875  16* Sample13 White Point & Filmed MB 1 5.19 17 Sample 11 White Filmed MB 1.18 2.5118 Sample 12 White Filmed MB 1.62 1.645  19* Sample 10 White Filmed MB*0.74 2.98 20 Table 2 Interior White Point & Filmed SMS 1.2 27.77 Example21 Table 2 Exterior Blue Point & Filmed SMS 1.2 21.465 Example 22 Table2 Interior White Point & Filmed SMS 1.85 25.185 Example 23 Table 2Interior White Point & Filmed SMS 1.85 30.24 Example 24 Table 2 ExteriorBlue Point & Filmed SMS 1.85 38.135 Example 25 Table 2 Interior WhitePoint & Filmed SMS 2.57 36.88 Example 26 Table 2 Exterior Blue Point &Filmed SMS 2.57 64.78 Example

FIG. 11 of the drawings is a graph that compares the Opacity Avg valuesfrom Table 2 and Table 4A & B. Examination of these results showsseveral unexpected results. These are generally as follows:

The unbonded MB samples (identified as MB White Unbonded in FIG. 11)have opacity values higher than the Interior White SMS Examples(identified as SMS White in FIG. 11), even when the basis weight of theunbonded MB is less.

Point bonding of MB decreases the opacity; interpolating an opacityvalue for an unbonded white MB sample at equivalent weight (i.e. %opacity of 85 from FIG. 11 for MB White at a basis weight of about 1osy) shows an ˜15% difference from the bonded white MB sample (Bonded MBWhite in FIG. 11).

The opacity contribution by the MB material to the white SMS is asignificant factor in opacity.

FIG. 12 of the drawings is a graph that adds the filmed Opacity valuesof Table 5 to the Opacity values taken from Tables 2 and 4A&B. Ofparticular note is that the Opacity for the 100% bonded White MB isessentially unchanged with respect to basis weight. Since the white MBhas no pigment added, the filmed MB is clear film. (The opaqueness ofthe unbounded MB comes from light reflectance off the surfaces of themeltblown fibers.) The filmed SMS white and SMS blue samples indicatethe opacity contributions from pigments.

Table 6 lists samples of two stacked plies to illustrate thecontribution to the resulting by the MB material. Sample Set 28 of Table6 represents the Invention Set of Table 3. Sample Set 27 in Table 6 isthe “Comp. Set 2” from Table 3. As given in Table 1, the MB contributionis 14-35%. Sample Sets 29, 30, and 31 have significantly more MBcontributing to the arrangements of two stacked plies because the weightof each of these 100% MB interior plies is greater than the MB in theinterior plies of Sample Set 27 and 28. Their Opacity values perColorimeter 1 are greater for a given Blue SMS exterior as shown in FIG.13 of the drawings which is a graph of information from Table 6.

TABLE 6 % OPACITY of 2 stacked plies with SMS components at: Sample 1.21.4 1.85 2.6 Set Description osy osy osy osy 27 Blue SMS/Blue SMS 90.6896.655 98.39 99.785 28 Blue SMS/White SMS 82.55 — 94.71 98.51 29 BlueSMS/Bonded 1 86.72 — 95.02 98.03 osy White MB 30 Blue SMS/Unbonded 89.43— 96.77 98.3 0.74 osy White MB 31 Blue SMS/Unbonded 93.86 — 96.31 100.821.18 osy White MB

One data point shown in FIG. 13 is for a filmed White SMS as an interiorply stacked on an Exterior Blue SMS ply of 1.85 osy. The filming(creating 100% bonded area as previously described by use of a desktoplaminator) shows a decrease in the two stacked plies by an Opacity valueof ˜5% per Colorimeter 1.

Table 7 lists samples of two stacked plies to further show the impact ofMB contribution on the resulting opacity. The Sample Sets listed in thistable are made by respectively stacking White interior plies of a givenmaterial over Blue exterior SMS plies at three different weights. Theopacity values resulted from Colorimeter 2 measurements and are theaverage of two individual values. Sample Sets 32 and 35 use White SMS asthe interior ply; Sample Sets 34 and 37 use White unbonded MB; SampleSets 33 and 36 use White bonded MB made from the corresponding unbondedMB of Sets 34 and 37 via thermal point bonding with a pattern (of FIG.3) to match that of the SMS plies. The resulting opacity values listedin the table are depicted in FIG. 14. Both the table and FIG. 14 showthat as the MB contribution increases for a given weight, the opacityincreases. Also, Table 7 and FIG. 14 show the impact of thermal pointbonding the MB: point bonding the MB in the interior ply, which reducesthe opacity in that ply (as demonstrated by comparing Table 4A and 4Bmatching opacity values), corresponding reduces the resulting opacityfor the two stacked plies. Thus, white fabrics with thermally pointbonded MB components are preferred for plying next to plies of greateropacity for the invention. Especially suited for the invention are whiteplies that have thermally point bonded MB weight contributions of lessthan 40%.

TABLE 7 Opacity for White Ply Sample over Blue SMS at OSY: Set White PlyDescription 1.20 1.85 2.56 32 SMS 2.56 osy 88.00 93.84 97.62 33 MB 2.56osy bonded 91.26 96.41 98.77 34 MB 2.56 osy unbonded 99.35 98.705 96.9135 SMS 1.20 osy 82.02 93.89 96.57 36 MB 1.20 osy bonded 88.56 95.0097.74 37 MB 1.20 osy unbonded 92.34 97.51 98.59

The preceding opacity values for the stacked plies result from the BlueSMS immediately over the specimen port and the White ply stacked overthe Blue SMS. Reversing the order of these stacked plies changes theresulting opacity. To illustrate this impact (reversing the order onplies on resulting opacity) Table 8 lists opacity values for selectedstacking of white and blue SMS plies in the opposite configuration fromTable 7: Sample Set 38 reverses the stacking for certain plyarrangements of Sample Set 32; Sample Set 39 reverses the stacking forthe 1.20 SMS plies of Sample Set 35. The resulting opacities are theaverage of two measurements via Colorimeter 2. FIG. 15 graphicallycompares the opacities of Table 8 to the corresponding related opacitiesof Table 7; reversing the stacking arrangement results in differentopacity values.

TABLE 8 Opacity for Blue Ply Sample over White SMS at OSY: Set Blue PlyDescription 1.20 2.56 38 SMS 2.56 osy 98.76 99.74 39 SMS 1.20 osy 89.35NA

The impact of the MB contribution on opacity is further detected when abreach in the Blue SMS exists. Tables 9 and 10 give opacity values thatare averages of two measurements per Colorimeter 2. For the sample sets,a breach of a 1.4 mm hole was punched (using a rod as previouslymentioned) into the Blue SMS plies. The SMS plies for Table 9 are: BlueSMS1 has a weight of 1.20 osy; Blue SMS2 has a weight of 2.56 osy. ForTable 9 the White plies respectively stacked next to the Blue SMS plieswere all of 2.56 osy but varied in MB contribution or thermal pointbonding: Sample Set 40 used unbonded white MB; Sample Set 41 used MBthermally point bonded with the pattern to match that used for the SMSplies; Sample Set 42 used white SMS. For Table 10 the SMS plies includethose for Table 9 plus Blue SMS3 that has a weight of 1.85 osy. TheWhite plies of Table 10 were approximately 1.20 osy but varied in MBcontribution or thermal point bonding like the White plies of Table 9:Sample Set 43 used unbonded white MB of ˜1.10 osy; Sample Set 44 used MBof ˜1.10 osy that was thermally point bonded with the pattern to matchthat used for the SMS plies; Sample Set 45 used white SMS of 1.20 osy.The resulting opacities in Table 9 and 10 were least for the respectivewhite SMS plies (regardless of stacking orientation against the specimenport of the colorimeter).

TABLE 9 Opacity for: Blue White Ply Blue White Ply SMS1 under SMS2 underSample White Ply under Blue under Blue Set Description White Ply SMS1White Ply SMS2 40 MB Unbonded 97.06 99.00 98.80 99.93 2.56 osy 41 MBBonded 91.94 97.31 95.25 99.31 2.56 osy 42 SMS 88.36 93.57 93.29 98.332.56 osy

TABLE 10 Opacity for: Blue White Blue White SMS1 under SMS3 under BlueSMS2 Sample White Ply under Blue under Blue under White Set DescriptionWhite SMS1 White SMS3 White under Blue SMS2 43 MB Unbonded 94.11 97.2296.53 99.55 97.98 99.43 ~1.10 osy 44 MB Bonded ~1.10 87.36 93.20 94.3999.06 98.47 99.14 osy 45 SMS 82.55 89.03 91.26 97.52 96.61 99.45 1.20osy

FIGS. 16 and 17 graphically show the respectively show the opacityvalues of Table 9 and 10 with respect to the type of White ply stackednext to the Blue ply. As shown in FIGS. 16 and 17, the white SMS plies,which have MB % less than 40% and thermal bond points, retain the lowestresulting opacity values when paired next to Blue SMS even with thepresence of a breach in the Blue SMS.

Thus, exemplary embodiments of the invention are presented herein;however, the invention may be embodied in a variety of alternativeforms, as will be apparent to those skilled in the art. To facilitateunderstanding of the invention, and provide a basis for the claims,various figures are included in the description. The figures are notdrawn to scale and related elements may be omitted so as to emphasizethe novel features of the invention. Structural and functional detailsdepicted in the figures are provided for the purpose of teaching thepractice of the invention to those skilled in the art and are notintended to be considered limitations. Directional terms such as left,right, front or rear are provided to assist in the understanding of theinvention and are not intended to be considered as limitations.

While particular embodiments of the present invention have beendescribed herein; it will be apparent to those skilled in the art thatalterations and modifications may be made to the described embodimentswithout departing from the scope of the appended claims.

What is claimed is:
 1. A sterilization wrap system comprising: anexterior panel comprising a permeable nonwoven material having barrierproperties and having a first surface and a second opposing surface, theexterior panel being substantially opaque or having a first level oftranslucence; and an interior panel comprising a permeable nonwovenmaterial having barrier properties and having a first surface and asecond opposing surface, the interior panel having a level oftranslucence that is higher than the first level of translucence of theexterior panel, wherein the level of translucence of the interior panelfalls within a range between substantially transparent and substantiallyopaque, wherein the interior panel includes a plurality of bond pointsand the bond points define discrete locations having higher translucencethan locations on the permeable nonwoven material of the interior panelthat are not bond points, wherein the panels are joined together over atleast a portion of their surfaces, wherein the higher level oftranslucence of the interior panel compared to the exterior panelfacilitates post-sterilization detection of breaches of the exteriorpanel when looking for light passing from the exterior panel of the wrapsystem through the interior panel of the wrap system after the wrapsystem is removed from a product that has been subjected to asterilization cycle, wherein the difference in translucence between theinterior panel and the exterior panel is at least 15 percent, whereineach of the interior panel and the exterior panel has a basis weightbetween about 1.2 ounces per square yard (about 41 grams per squaremeter) and about 1.85 ounces per square yard (about 63 grams per squaremeter).
 2. The system of claim 1, wherein the plurality of bond pointson the interior panel provide the interior panel with at least 15percent higher translucence than locations on the permeable nonwovenmaterial of the interior panel that are not bond points.
 3. The systemof claim 1, wherein the system is a steam sterilization wrap system. 4.The system of claim 1, wherein the system is an ethylene oxidesterilization wrap system.
 5. The system of claim 1, wherein theexterior panel and the interior panel are a single sheet of permeablenonwoven material having barrier properties, the single sheet beingfolded over to form the exterior panel and the interior panel.
 6. Thesystem of claim 1, wherein the exterior panel and the interior panel areindependent sheets of material.
 7. The system of claim 1, wherein theexterior panel and the interior panel each have a periphery and theexterior panel and the interior panel are overlaid and joined at theperiphery.
 8. The system of claim 1, wherein at least one of thepermeable nonwoven materials having barrier properties is aspunbond/meltblown/spunbond material.
 9. A sterilization wrap systemcomprising: a permeable nonwoven material having barrier properties, thepermeable nonwoven material including: an exterior sheet having a firstsurface and a second opposing surface, the exterior sheet beingsubstantially opaque or having a first level of translucence; and aninterior sheet having a first surface and a second opposing surface, theinterior sheet having a level of translucence that is higher than thefirst level of translucence of the exterior sheet, wherein the level oftranslucence of the interior sheet falls within a range betweensubstantially transparent and substantially opaque, wherein the interiorsheet includes a plurality of bond points and the bond points definediscrete locations having higher translucence than locations on theinterior sheet that are not bond points, wherein the sheets are joinedtogether over at least a portion of their surfaces, wherein the higherlevel of translucence of the interior sheet compared to the exteriorsheet facilitates post-sterilization detection of breaches of theexterior sheet when looking for light passing from the exterior sheet ofthe wrap system through the interior sheet of the wrap system after thewrap system is removed from a product that has been subjected to asterilization cycle, wherein the difference in translucence between theinterior sheet and the exterior sheet is at least 15 percent, whereineach of the interior sheet and the exterior sheet has a basis weightbetween about 1.2 ounces per square yard (about 41 grams per squaremeter) and about 1.85 ounces per square yard (about 63 grams per squaremeter).
 10. The system of claim 9, wherein the plurality of bond pointson the interior sheet provide the interior sheet with at least 15percent higher translucence than locations on the interior sheet thatare not bond points.
 11. The system of claim 9, wherein the exteriorsheet and the interior sheet are a single sheet of permeable nonwovenmaterial having barrier properties, the single sheet being folded overto form the exterior sheet and the interior sheet.
 12. The system ofclaim 9, wherein the exterior sheet and the interior sheet areindependent sheets of material.
 13. The system of claim 9, wherein theexterior sheet and the interior sheet each have a periphery and theexterior sheet and the interior sheet are overlaid and joined at theperiphery.
 14. The system of claim 9, wherein at least one of theexterior or interior sheets is a spunbond/meltblown/spunbond material.15. A method of using sterilization wrap system comprising: providing anarticle; wrapping the article with a sterilization wrap systemcomprising: an exterior panel comprising a permeable nonwoven materialhaving barrier properties and having a first surface and a secondopposing surface, the exterior panel being substantially opaque orhaving a first level of translucence; and an interior panel comprising apermeable nonwoven material having barrier properties and having a firstsurface and a second opposing surface, the interior panel having a levelof translucence that is higher than the first level of translucence ofthe exterior panel, wherein the level of translucence of the interiorpanel falls within a range between substantially transparent andsubstantially opaque, wherein the interior panel includes a plurality ofbond points and the bond points define discrete locations having highertranslucence than locations on the permeable nonwoven material of theinterior panel that are not bond points, wherein the panels are joinedtogether over at least a portion of their surfaces; exposing the wrappedarticle to sterilizing conditions for a sufficient time such that thearticle is sterilized; unwrapping the article and removing thesterilization wrap system; positioning the sterilization wrap system soat least a portion of one of the exterior panel of the sterilizationwrap system is opposite a viewer and a corresponding portion of theinterior panel is facing a viewer; and inspecting the sterilization wrapsystem for exterior panel breaches by looking for light passing throughthe interior panel facing the viewer, wherein the higher level oftranslucence of the interior panel compared to the exterior panelfacilitates post-sterilization detection of breaches of the exteriorpanel when looking for light passing from the exterior panel of the wrapsystem through the interior panel of the wrap system after the wrapsystem is removed from a product that has been subjected to asterilization cycle, wherein the difference in translucence between theinterior panel and the exterior panel is at least 15 percent, whereineach of the interior panel and the exterior panel has a basis weightbetween about 1.2 ounces per square yard (about 41 grams per squaremeter) and about 1.85 ounces per square yard (about 63 grams per squaremeter).
 16. The method of claim 15, wherein the sterilization wrapsystem is positioned so that the sterilization wrap system is locatedbetween a light source and the viewer.
 17. The method of claim 15,wherein the sterilization wrap system is positioned so that the exteriorpanel and the interior panel are separated by a space in a portion ofthe sterilization wrap system being inspected.
 18. The method of claim15, wherein inspecting the sterilization wrap system for exterior panelbreaches is carried out by looking for light passing through theinterior panel facing the viewer by way of one or more bond points.